Lock



Jun 8 1926. 1,587,686

G. VARNUM LOCK Filed April 1, 1924 3 Sheets-Sheet 1 Patented June 8,1926.

UNITED starr-2s GEORGE B. VARNUM, ,0F LOS ANGELES, CALIFORNIA.,

LOCK.

Application let April 1, 1924. Serial No.. 703,527.

This invention relates generally to locks andmore particularly to locksadapted for use in connection with safe deposit compartment doors wheretwo keys are required to 5 actuate the bolt mechanism, one key being inthe possession of the renter and the other held by the custodian orguard of the vault.

As one of the features of my invention, after the lock has been actuatedto alfow i the `con'ipartment door to be opened, the renters keymust beremoved from the key post before the guard key may be withdrawn; itbeing possible, however', for the renter subsequently to reinsert hiskey and shoot the bolt home without requiring insertion of the guardkey. l/Vhile the door` is open the renter may throw the bolt in eitherdirection by the sole use of his key, but when the door has been closedand the rente-rs key' has been used to shoot the `bolt home to lock thedoor, joint key application is again necessary to reopen the door. Theguard key, by itself,` is incompetent to lock the door.

Nhile the advantages of this system are many, I need mention but a fewof the more outstanding. For obvious reasons it is highly desirable,both to the vault proprietor and to the renter. that the renters keynever be left in the lock except in the presence. of the renter,although it is often a temptation so to leave it. Since the guard cannotwithdraw his key until the renters key is withdrawn, the withdrawal ofthe 35: customers key, in the'presence of the guard, is forced. for theguard dare not leave his post atthe compartment except when the gua-rdkey is actually` in his possession.

Since the'guard key, by itself, is incom- Lil? petent to relock thedoor, the renter is obliged to perform this task himself,u and sinceonly the tumblers of his particular compartment lock are responsive tohiskey, there is no liability of the renter locking` his 'i5 bond box inany compartment other than his own, Once the door is open,`the keyscannot be withdrawn, either singly or jointly, until the bolt has beenthrown to extended position, so, until the renter finally locks ffl thedoor, the door must either be open with the lock bolt extended or therenters key must be in the lock. Either of these circui'istances givesobvious notice of the condition of that particular box, and calls for Vfimmediate remedy in case the renter inadvertently or purposely leavesthe premises' without fulfilling his duty.

- Many of these features are disclosed in United States Patent No.1,489,042 to Var num, et al., but they are there shown vembodied in alockof the two nose type. The present invention is concerned with theapplication of these features to a single nose, two key lock, suchapplication involving certain distinct and novel differences over thestructure disclosed in the issued patent.

As a further feature, my invention may be appliedto an interchangeablekey lock", that is, a lock wherein the tumblers may be automatically setup to form proper combinations by the mere insertion and actuation ofany key of a given series. This is in distinction to locks whereinfit isfirst necessary to change `the tumbler combination and then Ele a key tolit that particular combination, or where it is necessary to disassemblethe lock and lit diHerently formed tumblers to a given key. ',By reasonof my 4provision and arrangement of certain elements, it is absolutelynecessary that the guard key be operated jointly and simultaneously withthe main or renters key when a 'new combination is set up. `Thisforestalls the possibility of the guard key being first used to set upthe guard tumbler and being then with drawn to leave the lock in suchcondition that a. second party may setthe combination to a main key inhis possession, `either accidentally or with fraudulent purpose. This isa feature of great value as has been proven by the fact thatinterchangeable key locks, without my safeguard, have actually been somanipulated, with aggravating and harmful results.

Other features of novelty and objects of the invention will be set forthin the following detailed description, reference being had to theaccompanying drawings in which:

Figure 1 is a horizontal sectional View of the forward wall of a safetydeposit com4- partment, showing, in elevation, the com pa-rtment doorand lock embodying my invention.

Fig. 2 is a View vsimilar to Fig. 1, but showingthe door in openposition and with the bolt in .extended position.

\ Fig. 3 is a front face view of the lock as it appears when detachedfrom the door.`

Fig. ishows a typical renters key.

Fig. 5 shows a typical guard key.

Gli'

Fig. 6 is a detached view of the key post makingup a part of the lockand illustrating the position the keys occupy with respect to the keypost when said keys are fully inserted. The key post is viewed from sucha position that the vupper or ward edges of the keys are presented tothe eye. v

Fig. 7 is a section on line 7 7 of Fig. 6 but with the keys omitted.

Fig. 8 is a view similar to Fig.'6 but showing the renterswkey, only,yas being inserted in the lock. V

Fig. 9 is a perspective view of a modified form of main key associatedwith a typical guard key.

Fig. 10 is a view of the lock with cover plate and vall tumblersremoved.

Figfll is a sectionon line 11-11 of Fig. 10.y

Fig. 12 is a view similar t0 Fig. 10 but showing the guard tumbler inlocking position.

Fig. 13 is a view similar to Fig. y12 but showing the boltpartiallyfretracted.

Fig. 14 is a view similar' to Fig. 13 butv showing the bolt extended andfree of the jamb or keeper.

Fig. 15 is a view similar to Fig. 14 but showing one of the maintumblers in place. Fig. 16 is a view similar to Fig. 15 but showing anadditional main tumbler in lace. y p Fig. 17 is a view similar to Fig.16 but showing the bolt partially retracted. Y

Fig. 18 is an enlarged section on line 18-18 of Fig. 17 showing thecover plate and nose in place.

Fig. 19 is a fragmentary elevation of a lock with a modified form of-key post; and Fig. 2O is an enlarged section on line 20-20 of Fig. 19.

At the outset, I wish to' make it clear that while I will describe myinvention as applied to a particular type of lock-that is. a dead-bolt.flat and interchangeable key lock-this is done for purposesofdescription only, and is not to be construed as limiting the inventiontoits application to any specific type of lock. It will be wellunderstood that the invention, in its broader aspects, may be equallyadvantageously embodied in a pin-tumbler, corrugated key lock, or to alock used in `connection with doors other than for safety-depositVcomcertain contingencies not successfully met in the past, so far as Iam aware.

First referring to Figure 1, the numeral 10 designates a door hinged at11 to one side of compartment casing 12. The bolt mechanism is containedwithin a casing 13 secured to door 10, and the main bolt 14 of the' lockis adapted to engage the usual slot 15 in keeper 16, the latter beingsecured to casing 12 in the usual manner.

Casing 13 is of box-like structure, having bottom plate 17, side walls18 and 18b and front and rear end Walls 19 and 20. A cover plate 21over-lies the bolt mechanism and is provided with the usual tubular eX-tension 22 which is adapted to project through door 10 whereby it isaccessible from outside the compartment. Extension 22 is known in theart as a nose and has an internal peripheral flange 23 which is notchedat 24 and 25 (in the present instance, said notches being diametricallyopposed) whereby actuating keys may be admitted to slot 26 in key post27 only when said key post is in predetermined relative position withrespect to said nose. Post 27 is mounted for rotation within nose 22 inthe usual manner, key post cam 28 coacting withwall 17 and head shoulder29 coacting with nose flange 23 in a manner to prevent longitudinalmovement of the post.

Bolt 14 ext-ends through a suitable aperture 30 in casing wall 19, andterminates in a tail piece 31 bearing on casing wall 17 and limited inits longitudinal movementby casing pin 32 which projects through slots33" in said tail piece. A slide plate 33 also bears on 'wall 17, and itis guided and limited in its longitudinal movement bv casing pins 34which extend through plate slots 35. A rack post 36, of staplelikeformation is mounted on and carried by plate 33, the plate being adaptedto be manually moved to the right in Fig. 10, under certain conditions,by a pin 37 which extends through a slot 38 in casing wall 17, and istherefore accessible only When the door is open. Normally, plate 33 isin the position of Figure 10,'that is, at the limit 'of its movement tothe left as viewed in lli sov located that there is clearance betweenall of its defining' walls with respect to pin 44 when the guard tumbleris in the position of Figure 12. At the forward end of tumbler 4G is anotch 45 adapted to receive bolt stump 46 when said stump and notch arein alinement. The extreme forward end of the guard tumbler has a lockingnose 47 and a riding nose 48, the lower shoulder 49 of nose 47 isadapted to bear on top stump 46, and the forward shoulder 5() of nose 48bears against the rear edge of stump 46 when the bolt is fully extendedand the door closed. The rearward end of tumbler 4() is provided with anotch 51 adapted to receive racking post 86, and a spring 52 actsbetween tumbler and casing wall 18 in a manner to move tumbler 40towards the opposite side wall'18b and thus maintains nose shoulder 49and shoulder 53 (defining the top of notch 51) in contact with the topsof stump 46 and racking post 36, respectively. i With the guard tumblerin this position tumbler lug 54 engages a stop pin 55 which extendsupwardly from casing wall 17. Thus, since tumbler 40 is held frommovement to the right, in Figui-e 12, by the engagement of lug 54 withpin 55, retractive movement of bolt 14 is prevented due to theengagement of stump 46 with shoulder 50; and in order to allow boltretraction tumbler 4() must be rotated about post 36 as a pivot untiltumbler notch registers with stump 46. When swung to this position,tumbler lug 54 clears pin 55. lVith tumbler 40 in the position of Figure12 and with lug 54 in engagement with pin 55 to prevent retraction ofthe tumbler and bolt, ,lug 56 on tail piece 31 engages lug 57 on slideplate 33 to maintain said plate against longitudinal movement to theright in this figure and therefore retains racking post 36 withintumbler notch 51. Gnly' when the tumbler is raised from engagement withpin 55 may slide plate 33 be moved to the right by manipulation of pin37, and such manipulation occurs only during a combination change.

The upper defining wall of tumbler aperture 42 is of such outline thatit provides oppositely inclined cam faces 58 and 61 with a horizontalface 79 extending therebetween. When guard key 41 is entered in the keypost, andturned in a clockwise `direction to bring it into the positionof Fig. 13, key ward 41, which extends into tumbler aperture 42, isbrought into engagement with cam face 58, swinging tumbler 40 in aclockwise direction about racking post 36 as a center and bringing notch45 into alinement with bolt stump 46, ward 41b thence moving` beneathface 79 to hold the tumbler in raised position. Subsequentcountercloclrwise rotation of key 41 allows spring 52 to return tumbler40 to locking position.

It will be noted that guard key 41, by

itself, is incompetent to impart longitudinal movement to the guardtumbler, and, therefore, the guard or holder of lrey 41, without themain key, is unable to shift the guard tumbler either to right or leftto hold it in unlocked or clear position. This is in contra-distinctionto the usual lock mechanism, wherein rotation of the guard lrey in onedirection lifts the tumbler to bring its notch into alinement with thebolt stump, and subsequent rotation of the guard key in the oppositedirection moves the tumbler longitudinally into such position that thetumbler notch remains in alinement with the bolt stump after the guardkey has been withdrawn. A

In order to insure that the frictional engagement between guard key andguard tumbler may not cause a longitudinal shift of the tumbler when thekey is rotated, l prefer to enter the end of spring 52 in casing notch92 (Figs. 12 and 13) out of which notch the spring end may ride when theguard tumbler is positively moved longit-udinally by means other thanthe guard hey, as will hereinafter be described.

It is also obvious that movement of the guard key, alone, cannot causebolt retraction since, as is usual t0 locks of this type, the maintumblers, to be described, cannot be thrown to release or clear positionby the guard key.

The main tumblers 63, 64 and 65 may be provided in any suitable numberand their forward ends are fashioned after the manner of theL forwardend of the guard tumbler er;- cept that the stump receiving notches 45bare of sumcient length to allow stump 46 full longitudinal movementwithout imparting1 like movement to the main tumblers. Each main tumbleris provided with a notch 66 to receive the key post and all maintumblers are held against longitudinal movement by reason of thepositioning pin 44 which eX tends upwardly through the arcuate tumblerslots 67, the latter being struck about riding noses 48b as centers. Therearward end of each main tumbler is serrated to provide combinationnotches 68, 69 and 70, in any ,suitable number, and depending upon thecombination, one of these notches in each main tumbler is adapted toreceive rackingpost 36. The combination notches extend radially fromnoses 48b as centers. Springs 71 are adapted to yieldably hold the maintumblers so their locking noses 47b are in locking engagement with thebolt stump, and it is obvious that depending upon the particularcombination notch entered by post 36, the distance of tumbler shoulders72 from -hey post 27 may be varied, thus calling for main key wards ofdifferent heights in order that, when the main lrey is inserted andinitially rotated in al clockwise direction, its wards may engageshoulders 72 in a manner nv. un'

[Iii

to rota-te or raise each tumbler so its notch comes into properalinementwith stump 4.6. Continued rotation ot' the key post by the mainkey throws key post cam 28 into engagement with shoulder 73 on tailpiece 31 and causes retraction of the bolt, provided, of course, guardtumbler' 40 is held in clear position, a position to which it can be putonly by use ot the guard key, and the guard key must be operatedsimultaneously with 'the main key in order that the guard tumbler becleared at the same time as the main tumblers. Subsequentcounter-clockwise movement ot key post 27 by the main key swings cam 2Sinto contact with shoulder 74 of tail piece 31, which throws the bolt toextended position, draws stump 46 from out notches 45", under certainconditions allowing the main tumblers to drop back into lockingposition, and also allowing the guard .tumbler to return to lockingposition.

Shoulder on slide plate 33 normally limits the rotation ot key post cam28, and hence key post 27 and themain key to less than 180o, andtherefore the key post cannot normally be rotated in a clockwisedirection sutliciently to allow withdrawal oft the keys through nosenotch 25, requiring that the bolt be shot to extended position bycounterclockwise movement ofthe key post betore the keys may bewithdrawn. I have shown above that it is necessary, when unlocking thedoor that the guard and main key be operated jointly and simultaneously,and I will now describe the means making it possible to relock the doorby using the renters or main key alone, it also being impossible to movethe bolt in either direction by the main key, alone, as long as the dooris open.

Generally, I accomplish this by moving the guard tumbler longitudinallyso as to hold it in unlocked or clear position, the movement beingbrought about by movement or the main bolt and its associated parts(rather than by movement of the guard key, as is true oi usual locks ofthis type). I utilif/e an auxiliary bolt for setting up thislongitudinal movement of the guard tumbler, and since the actuation ofthe auxiliary bolt depends 'upon circumstances which can only becontrolled by movement of the main'key or the main bolt 14, it will beseen that the renters key must be in the lock before the guard tumblermay be moved to hold it in unlocked position. However, the auxiliarybolt operates in such a manner that when the door is open itautomatically retains the guard tumbler in unlocked position so the boltmay be shot to and fro with the renters key alone, but after the rentercloses the door and shoots the main bolt home, the auxiliary bolt movesto allow the guard tumbler to return to locked position, so thatsubsequent unlocking of the door requires joint application of thel twokeys.

In the present embodiment ofthe invention the auxiliary bolt consists ofa lever pivoted to bolt 14 at 81 and having an arm lying adjacent theouter face ot said main bolt. Lever S0 also has a depending extension S3(Fig. 1]) which brings lever arm S4 into the plane ot guard tumbler 40,and the end ot arm S4 terminates in a hook 85. Lever 8O extends througha suitable aperture Sti in casing wall 19, and a `flat spring 87 on thislever is adapted to coact with pin 88 on bolt 14 to yieldably rotate thelever in a counter-ciockwise direction. Guard tumbler 4() has av notch89 formed in itslower edge and laterally deiined by lugs 54 and 90.

I' Then the door is closed and the main bolt shot to locked position asin Figures l and 12, it will be noted that arm 82 ot lever 80 engageskeeper 16 at one side ot the boltl aperture 15 and this engagementcauses the retention ot arm 84 in such a position that hook is out ofoperative engagement with the guard tumbler. To unlock the door theguard key 41 and main key 91 are simultaneously entered in the key postslot 26 which is of sutiicient width to accommodate both keys at once.For the time being We will disregard the peculiarities of the lock andkey which compel the entry and withdrawal ot the keys in certainsequence and will merely assume that both keys are capable of beingsimultaneously thrust into the lock. As key post 27 is initially turnedin a clockwise direction the guard key raises the guard tumber tounlocked position, and the main key raises the main tuinblers tounlocked position. Further rotation of the key post causes retraction ofthe main bolt by reason of the key post cam engaging tail piece shoulder78. This places the lock in the condition of Figs. 13 and 17, and, aspointed out above, it will be seen that since the guard tumbler isresponsive only to the guard key, and the main tumblers are re-`sponsive only to a particular main key, it is necessary that both be inoperative position within the lock before the bolt can be retracted, andsince the guard key is unable to move the guard tumbler to hold it inunlocked position, the main key mustl retract the bolt while the guardkey is holding its notch 45 in register with stump 46. i

To discuss the action of the auxiliary bolt on the guard tumbler it isunnecessary to consider the position of the main tumblers and thereforeFigures 12, 13 and 14 illusa trate the bolt mechanism with the maintumblers omitted. As bolt 14 (Fig. 12) is retracted by movement of thekey post cam 2S, spring 87 acts, by reason of pivot point 81 movinginwardly with the main bolt, to rotate lever 8O in a counter-clockwisedirection, moving tongue or catch 85 into the guard tumbler notch 89, asshown in Figure 13. Now assume that the door be opened and the key postbe turned back to original position in order th at the renter and .guardmay withdraw their keys. This means that the bolt must be shot yto fullextended position so as to brina,Y post slot 26 in register with notchHowever, since keeper 16 no longer lies in `the path .ot auxiliary bolt80, spring Si' .continues to hold bolt 8() in the position ot Figures 13and le. The extent of tumbler notch 89 is such that while the main boltis mowing to extended 'position` catch 85 engages lug 96 betore the mainbolt is lully extended and therefore draws guard lug #t0 .to vthe lettin l? i gure lit during the last part oi lmain bolt extension. rlhislongitudinal increment oit' guard tumbler l() prevents riding nose 'fromleaving stump 46 and thus the guard :tumbler is held elevated in clearposition while the main tumblers are returned to locking position. It is.evident that the main bolt may thereafter be thrown to and fro byactuation ol" the key post through the main key only, thus allowing therenter .to relock his box without calling 'tor joint action oit theguard key. Before the door be lclosed itis necessary that the rentertirst fully retract the bolt .by use .of his key, and 4in so doing, itstill being borne in mind thuttongue 85 is in notch 89, tongue S engagesguard tumbler lug 54 during the last .part ot bolt retraction and movesthe guard tumbler back to ,the right. Now, it the bolt be again ertendedwith the .door open, tongue 85 still 7functions, von the extensionstroke ot the main bolt, to retain nose i8 on stump 1&6 and thusmaintain the guard tumbler in clear position. However, when the door isclosed and the ina-in bolt shot home by the niai-n key, whether or notthe guard f be also in the key post. arm 82 engages keeper i6 ibetorethemain bolt :is fully extended.. and lever .SOis thereby rotated in aclockwise direction to release hook 85 from slot 89. rllhe guard tumblerl0 is thus lett in normal Condition, .as regards its longitudinalposition, and `consequently when the main bolt reaches its position otVfull ex-- tei .n guard tumbler 41:0 is tree to be urged do nwe-.rally.by spring` `and `thrust into locking position.

In lieu ot utilizina` the engagement ot hook with lug 54 Ytor thrustingthe guard tumbler back to normal posit-ion during main bolt retractionalter and immediately preceding bolt extension with the door open,notchi-t'i may be suliciently shallow to bring shoulder 62 in the pathot stump 4,6 during main bolt retraction, so said stump, in itsengagement `with said shoulder, moves the guard tmnbler back to normal.ln sucha case, notch 89 will be ot' `such an extent that hook isincapable ot engaging lug 54.

liVhen the combination is .to be changed, the following procediiire isfollowed. The bolt is first retracted by the use `of the two keys, asdescribed above, and the' door opened. The guard and main .tuniblerswill then be in .the position shown in Fig. 17., except that bolt llwill be :at the limit ot its retracted movement rather .than in thepartially retracted position shown in this ligure. VVitfh rthe bolt tailpiece 31 at the e3 ine limit ot its .retractiye movement, lug ...i6 isventirely clear ot slide plate lug 57. The slide slate :3B is .thenkmoved to the right as wie'wed in the various gures, by manualmanipulation ot pin 37, carrying with it the rack post 36. The post ismoved a .sufficient distance to .clear it Vfrom the combination notches68, 69 and 7.0 of the various marin tu-u'iblers land from notch .5l ot.the guard tumbler. Consequently, both Vguard .and main tuinblers yareswung .downwardly by springs 52 and 71 about noses i8 and 48h .ascenters. They are caught and supported bythe ,en gageniient .of tumblerracking noses 7 6 with racking `posit '36 the latter being limi-ted inits longitudinal increment .to such an extent that itcannot be broughtclear of said racking noses. Thus yall the tumblers, irrespective .ot`their previous relative positions, and irrespective ot which.combination notches were ,entered by the racking post, are dropped andheld 'in Aa common, neutral position, .this ,position being such ithatshoulders 72 .ot Athe main tumblers .clear the key post bya smallmargin. vSlide plate 33, in

its moyementito the right, .withdraws shoulder troni beneath keyposition cam 28. Therefore., `,tlfie key post may be further rotated ina clockwise direction to bring the key post slot 2.6 into neg-isterwithnose notch 25, whereupon the keys are withdrawn troni the lock. f

Then the guand key ,and :the new main key are entered through notch I25and are rotated in a counter-clockwise direction. In its rotation theguard key ward 41h .engages cani 'tace 61 iet" the guard tumbler,raising the ,rear endet said tumbler vso its notch 5l, is in alinementwith rack post 36. At the saine time, the various wards ot the main keypick up their ,corresponding tuinblers, and when the keys have reached aposition .ap-

proximately midway between their extremes,

key lpost @am 28 engages tail shoulder 7l and moves the -bolt gto :thelett. This movement ot the holt causes longitudinal movement yot slideplate due to Vthe coaction between t-ail piece lug 56 and Islide platelug 57, and consequently Aracking post 36 is drawn to the lett andenters thosecombination notches ot :the main tumblers which are nowV inalinement with said post, thus setting the tumblers to the new main keydue to lthe fact that the tumblers are at :their uppermost positioinasdeterminedby the individual key wards associated,therewith, at the timeotIV racking post entry to the notches. Since the guarditumbler :may notbe raised to bring notch '51 into line with post 3G except with the useof the guard key, the main key, by itself may not be used to set themain tumblers up to the newconibination for the following reason. Theshoulder 78 beneath the racking nose 76 of the guard tumbler would stillengage racking post 36, and if plate were moved to the left by theengagement of lugs 56 and'57 through main key actuation, tumbler 40would also be carried to the left.v The guard tumbler would then engagepin 44 to prevent full movement of plate 33 to the left and hence wouldprevent full main bolt extension, and such extension is neces sary toset the main tumblers to the new combination and to allow key withdrawalthrough notch 24. l

Vith the use of botlrkeys, however, all tumblers are first raised toybring their respective rearward notches into alinement with rackingpost 36, whereupon slide plate 33 and bolt 14 are free to move to theirfull extended position upon a counter-clockwise rotation of the keypost, the new combination being set up during the period of thismovement as previously described, slide plate 33 being` moved to drawracking post 36 into the registering notches of the various tuinblers.Thus it is `evident that it is necessary that the guard and main key bejointly and simultaneously applied to set up a new combination, thuseliminating the danger of the lock being left in such a condition thatany main key, by itself, may set up a new combination after a preceding,independent guard key actuation. i

It will -be understood it lies within the scope of my vinvention to varythe form and mounting of the auxiliary bolt within certain limits.l Forinstance, fiat spring 87 may be supplanted by4 a coil spring about pivot81, or arm 82 may be a straight thrust bolt mounted within main bolt 14and adapted to project beyond the end of said main bolt when the door isopen and brought flush with said end when the bolt is seated in itskeeper, the movement of said auxiliary bolt being transmitted to a catcharm similar to arm 84 by any suitable connecting means such as a link. f

I will now describe my preferred method of forcing a predeterminedsequence in the withdrawal of the keys'whereby the guard is forced tostay by the compartment until the renter has removed his key from thelock. It will be noted by reference to Figure 3 that while the keyreceiving slot 26 in post 27 is of suiiicient width to accommodate thetwo keys, side by side, notches 24 and 25 in the nose iiange are only ofa width to admitt he keys one at a time. Thus one key must bev insertedthrough notch 24 and moved laterally through the key postslot andbeneath the overhang of the nose flange before notch 24 is clear toadmit the other key. In order that the guard key necessarily be the lastwithdrawn. and conversely the iirst inserted, I have formed the keyreceiving slot 93 in key post cam 28 as illustrated in Figure, 7. Theportion of this slot which is in alineinent with key post slot 26 is ofa width suilcient to admit the two keys but the body of the cam projectsinto slot 93 at 94 to restrict the height of one-half of slot 93 withrespect to the other half. Thus, slot portion 95 is relatively long andslot portion 96 is relatively short. The'first ward 41b of guard key 41is so located that when the key is in operative position within the keypost and within slot portion 96 of cam 28, said ward lies at one side ofprojection 94. On the ,t other hand, the first ward 98 of main key 91 isso located that when said key is in operative positionthe ward lies inthe plane of cam 28 and projection 94. Therefore to place said main keyin operative position it is necessary that ward 98 lie within therelatively long slot portion 95. Thus projection 94 prevents the mainkey from being first inserted and moved bodily in such a manner that itclears the slot for subsequent insertion of the guard key, for, withward 98 in end engagement with projection 94, the main key may not bethrust inwardly a suiiicient distance to bring retention notch 99 inregister with nose flange 23, and such register is necessary to allowthe handle end of the key to be moved laterally through slot 26sulficiently to admit the guard key. In Figure 8 I have shown the mainkey 91 as being inserted to its operative position with respect to thekey post prior to the insertion `of the guard key, and in which positionward 98 lies within cam slot portiony if 95, and retention slot 99 is inregister with the nose notch 24. However, since projection 94 engagesthe side of ward 98 to hold the inner end of the key from lateralm0vement, an attempt to move the key laterally in a manner to clearnotch 24 merely resultsin an inclination of said key as shown in thisfigure. This leaves a wedge shaped opening at one side ofthe main key,and,

Bil

iix

of course, it is impossible to insert the guard key through such apassageway. On the other hand, ywith the main key in this position andwith rthe guard tumbler in unlocked position due to a previous joint keyaction, key 91 is competent to actuate the main tumblers, turn the keypost and reciprocate the main bolt.

In order to show that the invention, in its broader aspects may beapplied to a single nose lock wherein there are two separate keyreceiving slots, I have illustrated a modified' key post in Figures 19and 20. Nose 100 has the two notches 101 and 102, while key post 103 haskey receiving slots 104 and 105 separated by a web 106. Slot 105 is oisutiiciei'it width to allow bodily transverse movement Ot' guard key107. Notch 102, however is only of a width to admit guard key 107. Inweb slot 108 is a slide block 109 having cam inclines 110 on itsoutermost ends. This block is tree to slide through the web so as toproject into either slot 104 or 105. Now it' main key 111 be insertedprior to guard key 107, block 100 will be forced across slot 105 by saidkey, thus preventing subsequent insertion oi the guard key. However,with the guard key lirst inserted within slot 105, when main key 111 isinserted in its particular slot, block 100 engages the guard key andmoves it laterally to the position of Fig. 19, both keys then beingl inoperative position. Due to the restricted extent ot notch 102, the guardkey cannot be withdrawn from the key post until key 111 has (ii-st beenremoved to allow transverse movement ot block 109, whereupon guard key107 may be moved transversely to rbring it in register with withdrawalnotch 102.

In Figure 9 I have shown a modified type ot main key 112, said keybeingso constructed that, in its coaction with the guard key, sequential keywithdrawal is forced. "With this modilied type ot key in use, thepeculiarly shaped slot in the key post cam and a restricted nose notchneed not be provided.l lt will be noted that main ke 112 has a shoulder113 nea-r its handle end. Liloth the slot in the key post and the notchin the nose flange may be of a width to simultaneously admit the twokeys, though preferably the guard key will be the iirst inserted. lVhenthe two keys are in operative position they will be associated as shownin Figure 9, that is, shoulder 113 will be in engagement with shoulder114e of the guard key. It is sellE evident that shoulder 113 preventsWithdrawal oit guard key a1 while said main key is in the lock.

lllhile I have shown and described specitic embodiments ot my inventionI wish to make the reservation that this showing and description are tobe considered merely as illustrative oi and not restrictive on thebroader claims appended hereto, for certain Quang-es in structure,design and arrangenjient may be made without departing; Jfrom the spiritand scope ot these claims.

I claim:

1. In a single nose lock, a bolt adapted to `be operated `jointly by twokeys which are both insertable through the single nose, and means on thenose adapted to prevent withdrawal ot one `ot the keys from the lockwhile the other key is in the lock.

In a single nose lock, a bolt adapted to be retracted by sin'iultaneousoperation ot two keys which are both insertable through the single noseto bring their operating portions into a position ot mutual over-lap,and

means on the nose adapted to prevent with `drawal of the keys from thelock except in predetermined sequence.

3. In a single nose lock, -a bolt adapted to be operated jointly by twokeys which are both insertable through the single nose, and means toprevent withdrawal movement ot one of the keys from the lock until theother key is completely removed from the lock. i

t. In a single nose lock, a bolt adapted to be retracted by simultaneousoperation ot two keys which. are both insertable through the single noseto bring their operating portions into mutually m'ei-lappiiig positions,and means on the. nose adapted to prevent insertion and withdrawal oli'the keys through the nose except in sequence.

5. In a single nose lock, a key post, and a bolt operatively connectedto the post and adaptedto be operated jointly and simultaneouslyV by twokeys which are both insertable through the single nose, said key posthaving a slot adapted to accommodate simultaneously both keys with theiroperating portions in mutally over-lapping relation,

said lock nose having a notch ot a width which will accommodate the keysonly one at a time. f

0. In a single nose lock adapted to be operated jointly by tivo keys, abolt, a lock nose, a rotatable key post in the nose, and a cam on thepost operatively connecting `it to the bolt, said key post having akey-ie 'ceiving slot ot awidth to accommodate both keys simultaneouslyand being adapted to register iiritermittently with a key admittingnotch in the nose during rotation of the key post, said notch being ot awidth to accommodate the keys only onev at a time; the key post camhaving a key-receiving slot in alinement with and opening to the keypost slot and having a portion ot a width to take both keys andanotherportion of a width to take only one key, said last-named portion beingin alinement vwith the nose notchwhen the bolt is fully extended.l

7. In a single nose lock, a casing, a bolt in the casing and adapted tobe operated jointly by two keys, a rotatable key post l' "or the lockand having a single slot adapted to accommodate the two keys in side byside relation, the casingv having` a key admitting notch adapted tointermittently register with the key post slot during key post rotation.the notch and slot being ot such shape that; when they are in register,they form an ir regular opening which will receive but one key at atime.

8. In a single nose lock, a bolt adapted to be operated jointly by twokeys which are adapted to be simultaneously accommo` dated by the lock,means to prevent the operative insertion ot one key when the other keyis mthe lock but allowing the operative insertion of said other key whensaid one key is in the lock, and means on the nose adapted to preventwithdrawal ot' said one key when said other key is in the lock.

9. In a lock, a bolt, a key post o-peratively connected to the bolt andadapted to be operated jointly by two keys simultaneously accommodatedin side by side relation by the key post, one of said keys beinginsertable to operative position when tlie other key is in operativeposition within the post, and means on the post and said one key adaptedto coact in a manner to `prevent insertion of said other key to anoperative position when said one key is in operative position.

l0. ln a lock, a bolt, a key post operatively connected to the bolt andadapted to be operated `iointly by two keys simultaneously accommodatedin side by side relation by the key post, one of said keys beinginsertable to operative position when the other key is in operativeposition within the post, means on the post and said one key adapted tocoact in a manner to prevent insertion of said other key to an operativeposition when said one key is in operative position; and means toprevent the withdrawal of said other key when saidV one key is in thepost.

1l. In a lock having asingle key post adapted to accommodate two keys, abolt operatively connected to the key post and adapted to cooperate witha keeper and to be retracted by simultaneous operation of the two keyswhen it is in engagement with the keeper, and to be retracted byoperation of one key when it is out of engagement with the keeper; andmeans to prevent withdrawal of one of the keys from the lock when theother key is in the lock.

12. In combination, a casing, a door for the casing, a lock for the doorand embodying a bolt adapted to be moved into and out of engagement withthe casing, a tumblerl capable of both longitudinal and lateralmovement, said tumbler being adapted to hold the bolt extended intoengagement with the casing when the door is closed and tol belatererally moved by a key to allow retraction of the bolt fromengagement with the casing, and means in the lock adapted to move thetumbler longitudinally into a position to allow reciprocation of thebo-lt when the door is open.

13. In combination, a casing, a door for the casing, a lock .for thedoor and embodying a bolt adapted to be moved into and out of engagementwith the casing, a tumbler capable of both longitudinal and lateralmovement, said tumbler being adapted to hold the bolt extended intoengagement with the casing when the door is closed and to be laterallymoved by a key to allow retraction of the bolt from engagement with thecasing, and means on the bolt adapted to move the tumbler longitudinallyinto ya position to allow reciprocation of the bolt when the door isopen.

14. In combination, a door, a keeper, a bolt adapted to engage thekeeper, a tumbler capable of longitudinal movement, a movable catch onthe bolt and adapted to o eratively engage the tumbler and move itlbngitudinally during the extension movement of the bolt when the dooris open, a spring adapted to move the catch into operative engagementwith the tumbler when the bolt is retracted from engagement with thekeeper, said catch being` adapted to engage the keeper and to be movedthereby ont of operative engagement with the tumbler vwhen the door isclosed.

l5. In combination with a keeper, a door lock including a bolt, atumbler capable of both longitudinal and lateral movement, said tumblerbeing adapted to be moved laterally by a key to allow bolt retraction,and means in the lock and detachably connected to the tumbler adapted tomove the tumbler longitudinally into a position to allow reciprocationot the bolt when the door is open and after withdrawal of said key, saidmeans being adapted'to coact with the keeper and to be thereby moved outof connection with the tumbler when the door is closed.

16. In combination, a door, a keeper, a bolt adapted to engage thekeeper, a tumbler capable ot longitudinal movement, a movable catch `onthe bolt and adapted to operatively engage the tumbler and move itlongitudinall y during the extension movement of the bolt when the dooris open, said catch being adapted to engage the keeper and to be movedthereby out of operative engagement with the tumbler when the door isclosed.

17. In combination, a door, akeeper, a bolt adapted to engage thekeeper, a tumbler, a catch member pivotally mounted on the bolt, meansto move the catch member into operative engagement with the tumbler whenthe door is open, and means to move the catch member out of operativeengagement with the tumbler when the door is closed.

18. In combination with a keeper, a door, a door lock including a bolt,a plurality of tumblers adapted to be actuated by two keys when the dooris closed, certain of said tumblers being main tumblers and responsiveonly to one of the keys, another of said tublers being a guard tumblerand responsive only to the other key, said guard tumbler being capableof longitudinal movement into a position to allow bolt reciprocationwhen the door is open, and a movable catch on the bolt and adapted tooperatively engage the guard tumbler and move it longitudinally duringlongitudinal movement of the bolt when kthe door is open, said catchbeing adapted to engage the keeper and to be moved thereby out ofoperative engagement with the tumbler when the door is closed.

19. ln combination With a keeper, a door a door lock including a bolt, aplurality ot tumblers adapted to be actuated by tWo keys when the dooris closed, certain ot said tumblers being main tumblers and responsiveonly to one ot' the keys, another ot said tumblers being a guard tumblerand responsive only to the other key, said guard tumbler being capable ot longitudinal movement into a position to allow bolt reciprocation whenthe door is open, a movable catch on the bolt and adapted to operativelyengage the guard tumbler and move it longitudinally during longitudinalmovement the bolt when the door is open, said catch being Vadapted toengage the keeper and to beV moved thereby out of operative engage mentwith the tumbler when the door is closed and means to prevent Withdrawalof one ot the keys `from thelock While the other key is in the lock.

Q0. In combination, a door, a keeper, a bolt adapted to engage thekeeper, and means for operating the bolt and including a single key postadapted to receive two keys at once and requiring` both keys foractuation when the door is closed and one key when the door is open.

21.111 combination, a door, a keeper, a bolt adapted to engage thekeeper, means tor operating the bolt and including a single key postadapted to receive tivo keys at once and requiring both keys forVactuation when the door is closed and one key when the door is open',and means to prevent Withdrawal ot one of the keys from the lock Whilethe other key is in the lock.

22. ln an interchangeable key lock, a bolt, means tor operating the boltrequiring two keys tor actuation, and means for resetting thecombination ot the lock by the simultaneous actuation ot' tWo keys.

23; In an interchangeable key lock, a bolt, means ifor operating thebolt requiring tvvo keys iior actuation, and means for resetting thecombination of the lock and requiring the simultaneous actuation of tivokeys'for operation. Y

In an interchangeable key lock, a bolt, means for operating the boltrequiring two keys tor actuation, means for resetting the combination oithe lock by the simultaneous actuation oi' two keys, and means toprevent Withdrawal of one of the keys from the lock when the other keyis in the lock.

25. ln an interchangeable key lock, a bolt, a nose, Va key postoperatively connected to the bolt and adapted to be actuated jointly andsimultaneously by two keys, said post being rotatable Within the nose toa. plurality of positions Which admit ot' key insertion to andWithdrawal from the post through the nose, and means on the nose adaptedto prevent Withdrawal ot one ot the keys While the other key is in thelock Whenthe post is in any one ot said positions.

26. In combination With a keeper, a door, an interchangeable key lock onthe door, said lock including a bolt adapted to engage the keeper, means'tor operating the bolt requiring tivo keys `tor actuation when the dooris closed and one key When the door is open; and means tor resetting thecombination of the look by the simultaneous actuation ot two keys.

27. In combination with a keeper, a door, an interchangeable key lock onthe door, said lock including a. bolt adapted to engage the keeper,means for operating the bolt requiring two keys for actuation when thedoor is closed and one key when the Vdoor is open; and means `forresetting the combination ot the lock and requiring the simultaneousactuation oit two keys for operation.

In Witness that I claim the foregoing l have hereunto subscribed my namethis 21st day ot March 1924.

GEORGE B. VARNUM.

